JPS5951925A - Production of expansion molding of silane-modified propylene polymer - Google Patents

Abstract

PURPOSE:To produce a high expansion ratio foam, by molding, crosslinking and expanding, by heating, a resin composition prepared by adding a silanol condensation catalyst and a blowing agent to a silane-modified propylene polymer. CONSTITUTION:An expansion molding is produced by molding, crosslinking, and expanding, by heating, a resin composition obtained by adding 0.01-5pts.wt. silanol condensation catalyst and 0.1-20pts.wt. blowing agent to 100pts.wt. (A) a silane-modified PP obtained by reacting 100pts.wt. PP with 1-50pts.wt. polybutadiene, 0.1-20pts.wt. organosilicon compound containing an Si-bonded hydrolyzable organic group and a CH2=C= group-terminated Si-bonded group and 0.01-5pts.wt. free-radical generator at a temperature at which the resulting mixture can flow, or (A') a mixture containing the silane-modified PP and PP and further containing at least, 0.1pt.wt., per 100pts.wt. this mixture, organosilicon compound as used in the silane modification reaction for obtaining polymer A.

Description

[Detailed description of the invention] □The present invention relates to a silane-modified propylene vehicle assembly.

An organosilicon compound having (a) at least one hydrolyzable organic group bonded to silicon and (b) a radical site and a reactive group generated in the polyolefin is added to the polyolefin at its flow initiation temperature. Silane-modified polyolefins obtained by reaction (generally referred to as a graft reaction) in the presence of a free radical generator at temperatures above are already known. This molded product of silane-modified polyolefin can be made into a crosslinked product by contacting it with water (including steam) in the presence of a silanol condensation catalyst, and in history, it has been possible to make a foamed product by combining crosslinking and foaming. can. In addition, since this silane-modified polyolefin has polarity due to silane modification, it has greater affinity with inorganic fillers than polyolefins that generally do not have polarity, and its blending can also achieve excellent reinforcing effects. can.

In the conventionally known silane modification method of polyolefin,
When polyethylene or a copolymer mainly composed of ethylene is used as the polyolefin, useful N-run modified polyolefins and crosslinked products thereof can be obtained, but polypropylene or copolymers mainly composed of propylene (
When using propylene polymers (hereinafter referred to as propylene polymers), the scission of the main chain of polypropylene etc. occurs preferentially over the grafting reaction of silicon compounds, making it impossible to obtain a polymer-modified propylene polymer that can be put to practical use. Further, even when a molded product obtained by adding a ranol condensation catalyst to this modified propylene polymer is treated with hot water, the melting index does not decrease so much, the amount of insoluble gel is small, and the mechanical properties of the molded product are not improved. Therefore, this silane-modified propylene polymer cannot be sufficiently foamed.

For this reason, when using propylene polymer, a method has been proposed in which a quinone dioxime compound or an acrylic compound is added as a crosslinking aid to prevent main chain scission of the propylene polymer. reaction is likely to occur,
For example, in the case of extrusion molding, this not only damages the appearance of the molded product, but also increases the load on the extruder, often making extrusion impossible, which poses a problem in the production of Q-foam.

The present inventors have discovered the present invention as a result of intensive research aimed at improving the drawbacks of such known silane-modified propylene polymers and providing a method for producing a foam with a high expansion ratio. .

The present invention provides (a) a propylene polymer, (b) a polybutadiene, and (c) an organosilicon compound, which has at least one hydrolyzable organic group bonded to silicon and a terminal C
a free radical generator having at least one group bonded to silicon having an H2=C<group; The gist is to produce a foam by molding, crosslinking, and heating and foaming a resin composition in which a silane-modified propylene polymer obtained by silane-modified propylene polymer is blended with a ranol condensation catalyst and a blowing agent.

The propylene polymer used in the ifJ 7-run modification reaction includes crystalline polypropylene, atactic polypropylene, a copolymer containing propylene as a main component with α-olefin (including ethylene and styrene), etc. Examples include graft polymers such as vinylpyridine, mixtures thereof, and mixtures containing these as main components with other thermoplastic resins.

The organosilicon compound used in the silane modification reaction described in Section 11 must have at least one organic group bonded to silicon and capable of decomposing water. Examples of such groups include alkoxy groups, particularly easily hydrolyzable lower alkokyne groups (i.e., those having 6 or more carbon atoms) such as methoxy, ethoxy, butquine groups; acyloxy groups such as formiloquine, acetoxy, gropionoquine groups; (OH3
)2C=NO-, 02H5(OH3)O=NO-, (0
6H5) Oxime group such as C=NO, -: H(OH3
)N-, H(C!2H5)N-.

Mention may be made of substituted amino groups such as H(C6H5)N-.

Among these, alkoxy groups are preferred because they yield relatively harmless and non-corrosive hydrolysis products.

This hydrolyzable organic group causes the silane-modified propylene polymer to have crosslinking properties and affinity for inorganic photo-filling.

Furthermore, the organosilicon compound conveniently used in the silane modification reaction must have at least one group reactive with free radicals and bonded to silicon. Preferable such groups are terminal Cll2-C<$
, especially a hydrocarbon group or a hydrocarbonoxy group. Examples of these are vinyl, allyl,
etc. can be mentioned.

Such free radical-reactive groups enable silane modification of the propylene polymer in the present invention.

As long as the organosilicon compound contains at least one of the specific water-decomposable group and a group having a terminal aH2we< group bonded to silicon, the remaining substituents on silicon are preferably The remaining 1-9 substituents, which are not particularly limited as long as they do not cause any atomization reaction, may be an alkyl group such as methyl, ethyl, propyl, octadenyl, or an aryl group.

Therefore, examples of organosilicon compounds used in the 7-run modification reaction of 11S include methylvinyldimethoxysilane, phenylvinyldimethoxy 7-silane, methylvinyldiacetoxy 7-rane, vinyltriacetoquine silane, and methylvinyldiacetoquine musilane. , allyltrimethquine 7 runs,
Mention may be made of vinyltrimethoxysilane, vinyltriethquinsilane and gammamethacryloxypropyltrimethoxysilane.

Preferred organosilicon compounds used in the silane modification reaction are general 2RR'5iX2 (where R is a hydrocarbon group or a hydrocarbonoxy group having a terminal 0H2=O< group, or is hydrolyzable). is an organic group,
R' is R or X.

A silane represented by each R (when there are two R's) and each xFi may be different from each other, more preferably a silane represented by the general formula R81X3 (where R and The silane represented. Most preferred are vinyltrimethynesilane and vinyltriethoxysilane.

b of the organosilicon compound used in the silane modification reaction;
i: i, t, depending on the desired degree of crosslinking, 0.1 to 0.1 to 100 weight ji +flS of the propylene polymer
It is preferably 0.5 to 10111 parts, more preferably 0.5 to 5'mm parts. This bolt is 0,
If the amount is less than 1-zz (lt part), the degree of crosslinking of the crosslinked product will be low and the packaging will be insufficient. On the other hand, if t5 is 20 parts by weight or more, a foam with a sufficient expansion ratio can be obtained.

Also, within this range, a good reinforcing effect is exhibited by blending the inorganic filler.

The polybutadiene used in the silane modification reaction includes 1,2-polymerized polybutadiene, 1.4-polymerized polybutadiene, and those whose terminals are chemically modified with idroxy groups, carboxyl groups, etc., or in the presence of maleic acid or acrylic acid. However, from the viewpoint of the effect of preventing internal cleavage, 1.2-polymerized polybutadiene containing pendant vinyl groups (including those whose terminals are chemically modified as in the above 6 pins) is preferable. Liquid polybutadiene having a molecular weight of 3000 or less is preferred from the viewpoint of being able to be mixed with a propylene polymer using a simple mixer.

The amount of polybutadiene used in the silane modification reaction is 1 to 50 parts per 100 parts of the propylene polymer, preferably 3 to 20 parts, more preferably 3 parts.
~15 NM parts is good.

If the amount is less than 1 part by weight, the effect of preventing main chain scission of the propylene polymer will be small, and the melt viscosity of the silane-modified propylene polymer will become low, making it difficult to form a foam, which is not preferable. On the other hand, if the amount of polybutadiene used is more than 50 parts by weight, the mechanical properties of the foam obtained from the silane-modified propylene polymer according to the present invention will deteriorate and the modification effect will be reduced, which is not preferable.

The free radical generator used in the silane modification reaction is a compound that can generate free radical sites in the propylene polymer under reaction conditions F and has a half-life of 6 minutes or less at the reaction temperature. If so, you can use it.

Such compounds include organic peroxides and peresters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-di(permyl peroxide/) ate. ) Hexyne-3,1,3-bis(t-butylperoxyisoglopyl)benzene, lauroyl peroxide, t-butyl peracetate, 2,5-dimethyl-2,5-di(t
-butylperoxy7)hexyne-3,2,5-dimethyl-2,5-di(1-butylperoxy)hexane, t-
Mention may be made of butyl perbenzoate, as well as azo compounds such as azobisisobutyronitrile, dimethyl azobutyrate, and the like.

The amount of these radical initiators used is 0.01 to 5 parts by weight based on the propylene polymer, preferably if 0
605 to 2 parts by weight. If the amount of the free radical generator used is larger than the above range, the main chain of the propylene polymer of No. 11 will be severed, resulting in a decrease in molecular weight and insufficient foaming, which is not preferable. In addition, the amount of the free radical generator used is 0.0 ], , ii
If the amount is less than 1 part, the kraft rate of the organic silicon compound will decrease, and the degree of crosslinking of the 7-run modified propylene polymer subjected to 4W will be low, resulting in insufficient foaming, so it is preferable.
Walking.

The reaction of the propylene polymer, polybutadiene, and organosilicon compound is carried out at a temperature at which the mixture becomes fluid, and extrusion (extrusion, roll, Panbury mixer, etc.) can be used.Extrusion When using a machine, the temperature of the highest part of the barrel and die is slightly lower than that of normal extrusion 1'70℃~250℃
It is best to keep it at around ℃. When liquid polyphthalene is used, a silicon compound and a free radical generator are mixed with RiWl on the surface of the propylene offshore granules or powder. They may be dispersed and heated, and in some cases, they may be added directly into the above-mentioned apparatus 1 (r1).

The silane-modified propylene polymer obtained in this way has a degree of foaming of 9 r
fQ body can be obtained. In order to cause this crosslinking, it is usually necessary to mix a silanol condensation catalyst (often used as a masterbatch) with the used surface of the 12/ran modified propylene polymer and mold it. It is recommended that the silane be exposed to water (usually hot water or hot steam).However, if it is possible to keep the 7-run modified globulin car combination substantially free of contact with water, the silane may be exposed to water (usually hot water or hot steam). It may be added and mixed to the silane modification reaction system before synthesis or to the raw materials for the reaction after synthesis of the modified propylene polymer and before storage.

If the water present in the water is sufficient to promote the crosslinking reaction, and a silanol condensation catalyst is present, the reaction between the 11J-modified propylene polymer and the water in the air will proceed and crosslinking will proceed. When crosslinking progresses to an extreme extent, the melt viscosity during extrusion molding or injection molding decreases significantly, resulting in an increase in load, or even in cases where the melt does not flow and molding cannot be performed.Therefore, it is usually necessary to remove the silanol condensation catalyst immediately before molding. It is desirable to mix and match.

The condensation crosslinking reaction of the 7-run modified prohylene compound of the present invention (containing a silanol condensation catalyst) can be suitably progressed by contacting it with water or steam, but in this case, the reaction rate decreases as the temperature increases. Therefore, it is generally preferable to carry out the reaction at a temperature of 60°C or higher.

Crosslinking of the silane-modified propylene polymer of the present invention can also be caused by heating the condensate in the presence of a shredded silanol condensation catalyst to around its melting point.

Examples of silanol condensation catalysts that can be used in the present invention include:
dibutyltin dilaurate, stannous acetate, stannous octanoate
Carboxylate salts such as tin, lead naphthenate, zinc calylate, iron diethylhexanoate, cobalt naphthenate; titanate esters; and metal compounds such as chelate compounds, such as tetrabutyl titanate, titanic acid Tetranonyl ester and bis(acetyl-acetonitrile) diisoglobyl titanate: Yes + itt 1
4 groups, such as ethylamine, hexylamine, and pyridine. Suitable catalysts are organotin compounds such as diptyltin dilaurate, diptyltin diacetate, and dibutyltin dioctate.

The silanol condensation catalyst is preferably used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the silane-modified propylene polymer.

The physical properties of the modified propylene polymer used in the present invention are significantly improved, and on the other hand, the strength of the material is also improved by adding inorganic filler 44. By combining the combination of crosslinking and inorganic light, the monthly yield strength is further improved.

Conventionally, in order to improve mechanical properties, particularly strength, etc., polypropylene has been mixed with 4-5 fillers. However, since polypropylene does not have permeability and has poor reactivity, a good reinforcing effect cannot be obtained even when an inorganic filler is mixed therein.

In order to improve the affinity between the filled side and the resin, there is a method of treating the filled side with a coupling agent. but,
In this method, a strong reinforcing effect is observed mainly in polar resins, but no significant effect is obtained in non-polar resins. In addition, the process of treating the filler with a coupling agent is complicated, and the treatment of fillers with a large specific surface area, which is particularly useful for improving properties, requires a large amount of coupling agent, which is uneconomical. There is a tendency for the effect of the processing agent to appear, weakening the improvement effect of the filling side on stiffness, electrical properties, etc.

On the other hand, the silane-modified propylene polymer used in the present invention has branches of silanol groups in its molecule, which enables strong bonding with the inorganic filler side. By adding condensation crosslinking, the mechanical properties can be improved by four times.

In the present invention, the filler may be added at any time before the silane-modified propylene polymer becomes crosslinked and no longer melts. For example, during the silane modification reaction, it may be supplied to the reaction system as it is or mixed with any of the raw materials in advance. , and may be subsequently molded.

When mixing the silane-modified propylene polymer with the inorganic filler and the silanol condensation catalyst, they can also be mixed by putting them into a full direct injection molding machine or the like. A more preferable method is to add the inorganic filler to the 7-run modified propylene il to improve the dispersibility of the filler and the silanol condensation catalyst. A method of adding a masterbatch and injection molding; when making a masterbatch of a silanol condensation catalyst, also add an inorganic filler side, melt and mix it to make it into granules, and then process it by injection molding, etc. in addition to coalescence. Method: One star patch of a silane-modified propylene composite, an inorganic filler and a silanol condensation catalyst is mixed in an extruder to form granules, which is then injection molded.

Inorganic fillers commonly used as inorganic fillers that can be used in the present invention include mica, glass,
Examples include metal oxides, silicon carbide, various metal powders, talc, clay, asbestos, and various metal oxides. All of the compounds listed here are particularly effective because they form strong bonds with silanol groups.

The usage of these fillers varies depending on the properties to be improved, but in general, the silane-modified propylene 1 coalescence used in the present invention (or the total amount of raw materials forming this)
5 to 100 parts by weight per 100 parts by weight, preferably lO
~7ON Homabe is good. When less than 5 parts by weight is used, the reinforcing effect of the filler is weak, and when more than 100 parts by weight is used, the moldability of the composition deteriorates, which is not preferred.

The blowing agent may be added at any time before the silane-modified propylene polymer ceases to melt due to crosslinking. For example, during the 7-run modification reaction, it may be supplied to the reaction thread as it is or mixed with any of the raw materials in advance, and after the reaction, a silanol condensation catalyst or an inorganic filler may be added to the silane-modified propylene polymer as desired. They may also be mixed together. The blowing agent is mixed with the silane-modified propylene polymer using a known method such as a Henschel mixer, a Banbury mixer 1 extruder, etc., to prevent decomposition of the blowing agent.
This is usually carried out by melt mixing at temperatures between i'0 and 200 C, followed by shaping.

The blowing agents that can be used to obtain a foam using the silane-modified propylene polymer of the present invention include N-N'-dinitrosopentamethinonetetramine azodicarbonamide,
Trihydrazinotriazine, anodicarbonamide,
Trihydrazinotriazine, P-toluenesulfonyl semicarbazide, barium azodicarboxylate, 4.
Organic blowing agents having a decomposition temperature of 140°C or higher are preferred, such as 4'-diphenyldisulfaonylazite and diphenylsul7one-3,3'-disulfonylhydrazide. Blowing agents that decompose to release carbon dioxide, such as soda bicarbonate and ammonium carbonate, can also be used. The blowing agent is the 7-run modified propylene polymer 100 at or below the temperature at which foaming occurs, such as methyl chloride and pentane.
Weight to part: 0.1 to 20. It can be used within the range of IL parts, and the amount used can be arbitrarily changed depending on the type of blowing agent and the target foaming ratio.

It is preferable that the heating source for foaming has a temperature equal to or higher than the temperature of the foaming agent. Usually selected from the range of 170 to 250C.

According to this foaming method, it is possible to easily obtain a stable quality foam with excellent strength, rigidity, heat resistance, uniform closed cells, and high magnification. It can be used for a wide variety of applications, including phase, insulation, backing, and sealing.

Sila/modified propylene 11 according to the present invention described above
The silane-modified propylene polymer can be replaced with a mixture of the silane-modified propylene polymer and a propylene polymer in the crosslinking, inorganic filler compounding, and extrusion process, and this case is also encompassed by the present invention.

It should be noted that the "mixture" referred to here refers not only to a mixture of the silane-modified propylene polymer and the propylene (Jt) polymer before mixing with the inorganic filling material, but also to a mixture of either one of the M1
It also includes a mixture of these 11I aggregates which is produced when the aggregate and the inorganic filler are first mixed and then the other polymer is added and mixed. this! Assisted synthesis The total amount of the silane-modified propylene polymer and propylene 11 [combined] is 100 l/1 part by weight, and the organosilicon compound used in the silane modification reaction to obtain the silane-modified propylene polymer is 0.1 weight. It is better to make it more than 100%. In this case, the side combination of the silane-modified propylene polymer is 5O11 to ensure sufficient crosslinking.
It is preferable that the amount of X is equal to or greater than the amount of melon. Note that the range of appropriate amounts of the silanol condensation catalyst, inorganic filler, and blowing agent based on 100 parts by weight of the silane-modified propylene polymer is as follows: The usage amount can be within a certain range.

The foam according to the present invention may contain antioxidants, ultraviolet absorbers, antacids, antistatic agents, lubricants, etc. that are usually added to propylene polymers.

When the silane-modified propylene polymer used in the present invention is molded by itself or when mixed with a propylene polymer, inorganic filler, etc., it is much more moldable than when molded using a normal propylene polymer. It also has the significant advantage that the temperature can be lowered, and this is not due to a lower melting point, but is due to a better flow of the melt. This reduces molding cycle time and improves productivity.
Also, utility costs can be reduced.

The present invention will be specifically explained below using Examples.

Example I 30 parts of MFR2,5 crystalline polypropylene powder and 3 parts by weight of a blowing agent azodicarbonamide were mixed in a mixer, and to this were added a double cap of vinyltrimethoxysilane and 2 parts by weight of a blowing agent azodicarbonamide.
．． A mixture of 30.2 mJj parts of 5-dimethyl-2,5-di-t-butylperoxyhexane dissolved and mixed in 5 parts by weight of 1-2 polymer liquid polybutadiene was added to make the surface of the polypropylene powder uniform. coated. This, MF
70 parts by weight of polypropylene granules having R2,5 were added and mixed uniformly at room temperature. To 95 parts by weight of this mixture, 100 parts of crystalline polypropylene powder of M P' R2,5 and 1 part of dinbutyltin dilaurate were added to Qf Add 5 parts of condensation catalyst master patch (B) obtained by extrusion molding into granules, mix with a V-type mixer, and melt-mix this mixture using a 30FllIφ pent-type screw extruder under the following conditions to obtain granules. was molded.

Barrel temperature Zone 1 160C 12170C #3 180C 141.90C Gui temperature 190C Screw rotation speed 5Qrpm The residence time of the polypropylene in the extruder was 2.5 minutes.

This granular material was kept in a press kept at 180°C for 5 minutes, then a pressure of 100Kf/- was applied and held for 2 minutes, and then transferred to a cooling press and cooled to room temperature while applying a pressure of 150kf/cd to a thickness of 11 A sheet of / was molded.

The sheet was then exposed to hot water at 100° C. for 24 hours to complete condensation crosslinking.

When this sheet was subjected to a pressure of 100 kg/cj at 200°C and maintained for 20 minutes, the pressure was released, and the apparent specific gravity was 0. A highly foamed body having uniform fine closed cells of o88t/cr/l was obtained. The percentage of insoluble gel in this foam was 67%.

Diagnosis Example 1 According to the formulation shown in Table 1 (numbers indicate parts by weight), vinyltrimethoxysilane, 2,5-dimethyl-2,5-di-t-phthylno;-oxyhequinone-3, average molecular weight 11
'1000 mono- and dipolymerized liquid polybutadiene, V
FR2,5 crystalline polypropylene granules and MI
The high-density polyethylene granules of No. 5.1 were melt-extruded using the same extruder as used in Example 1 under the same conditions to obtain 7-run modified propylene polymer granules (A).

Next, a diptyltin dilaurate masterbatch (B) prepared in the same manner as in Example 1 was blended into 1iiJ in the same manner to obtain granules (0).

Next, (0) was heated in a press kept at 180°C for 8 minutes, then a pressure of lOOKp/ad was applied, and after keeping at the same temperature for 2 minutes, it was taken out and transferred to a cooling press, with a pressure of 150kg/- still applied. Cool to room temperature and thickness 0.311
11 sheets were molded (D). .

C) This sheet was condensed and crosslinked by exposing it to hot water at 100C for 24 hours.

, MFF+ of (A), (0), (I)) and F) are shown in Table 1 together with the formulation.

From this table, it is estimated that the effect of the present invention is observed even in a mixture of crystalline polypropylene and high-density polyethylene, and in that case, even when the crystalline polypropylene is 50% by weight.

Reference Example 2 2 parts by weight of vinyltrimethoxine oran and 2,5-dimethyl-2,5-di-1-butylnoζ-oxyhexine-30
MFR (Melt Flow Sheet); 2: When a load of 2.16 kg at 30°C was added to a 5-layer plate of 1/2 polymer liquid polybutadiene having an average molecular weight of 1000 and thoroughly stirred and mixed. The surface of the granules was coated with 100 parts dispersed in crystalline polypropylene granules of 2°5 (fit(r)) for 10 minutes from a predetermined cylinder. The coated granules were then prepared in Example 1.
F6 melt extrusion was carried out under the same conditions using the same extruder as used in , to obtain silane-modified propylene polymer granules (A).

The MFR of the obtained granules (A) was 31.

Next, 100 parts of heavy liquid of the same crystalline polypropylene granules as used in the production of (A) were added with 1 part of dibutyltin dilaurate.
of the mixture was added and extruded into granules using the extruder sound to obtain a master knife (B).

V
The mixture was mixed using a mold mixer and extruded using an extruder to obtain granules (0).

Next, a sheet was molded from Section 110 (C) in the same manner as in Reference Example 1 and treated with hot water to obtain a crosslinked sheet (E).

Table 5 shows the MFR of No. 111J (0), (D), and (K) together with the mixing ratio.

Table 2 From Table 2, it is clear that although a certain degree of effect is recognized even when the ratio of the former to the total amount of modified polypropylene and poly7"ropylene is A, a remarkable effect appears when it reaches 80%.

that's all Patent applicant: Chinono Co., Ltd. Agent: Patent Attorney Yatabe Sasai

Claims (2)

[Claims] (1) (a) GutJ pyrene J (L combined 10,031 parts by weight, (b) 1 to 50 double parts of polinkjiev, (c) a 41-organic silicon compound that is bonded to silicon and has at least 1 mil
0.1~20Φ1xL fm, and a free radical compound having two hydrolyzable Minamiiso groups and a terminal CH2-C< group and at least one group bonded to silicon. By reacting 0.01 to 5 ice parts of the crude agent at the temperature at which these mixtures flow, fη is reduced7.
A mixture of lan-modified glopylene polymer (1) or a combination of this and noropylene and chlorophylene, which was used in the silane-modified reaction process for preparing the 1+i modified glopylene subpolymer.
iiJ gt 4J silicon compound to 100% of the mixture
Contains 0.1ffi part or more for each part (1
' ) VciU written component! Or a resin composition containing 0.01 to 5 M, 1fI part of the 7-lanol condensation catalyst (n) and 0.1 to 20 parts by weight of the blowing agent (10) per 100 parts by weight of A method for producing a foam, which is characterized by molding a material, crosslinking it, heating it, and foaming it. (2) The method for producing a foam according to item (8), wherein the resin composition contains 5 to 100 parts of an inorganic filler based on parts of X0O of the component 1.